After every training session, your fitness declines. It sounds cruel but it’s true. Key is to recover from this workout and get fitter. But how much recovery is enough and how much recovery is too much? Heart Rate Variability can measure whether you are training too much, or not enough!
Imagine you just did a 10k run or a 30-minute strength workout. Immediately afterwards you feel fatigued. If you had to do the same 10k run or 30-minute strength workout again, you would probably find it harder than the first time. Maybe it would not even be possible to do it again. So, there you go. After every training session, your fitness declines.
If you take it easy afterwards, eat properly and have a good night of sleep, you will recover from the workout. Depending on the intensity of the workout, you will recover within 1 to 2, maybe 3 days. After the recovery you will be as fit as when you started the workout. When you pay enough attention to the recovery phase, you will even get a bit fitter than before. Recovering above your initial fitness level after a workout is called supercompensation.
Supercompensation is what we all aim for. You don’t work out to get less fit, you want to get fitter. The key to success is not (only) a good workout, but enough recovery afterwards. Training without recovery will only get you fatigued. Training with too much recovery will bring you back to your old fitness level because of inactivity. But how do you stay on the thin line between not enough recovery and too much recovery. To measure is to know.
When exercising, the body is pushing the gas pedal via your sympathetic fight or flight system. When recovering, the body is pushing the brake pedal via your parasympathetic rest and digest system. A balance between the gas- and the brake pedal is what we aim for when combining exercise with recovery. Your heart rate variability can tell you something about that balance.
Your heart is not a metronome. When you have a heartrate of 60 beats per minute, the time between the heartbeats is 1 second on average. The actual time between heart beats differs. For instance, 0.8 sec – 1.1 sec – 1.0 sec – 0.9 sec etc. The variation in the time between heartbeats is called heart rate variability.
In general, the higher the heart rate variability, the better you are recovered. You are ready to train again. A low heart rate variability is a sign that you are not fully recovered yet. This could be caused by inadequate recovery from exercise, but also from other stressors in life. In other words: one metric tells you whether you are ready to train, or should take some extra rest.
It might sound like abracadabra. Studies however show, that adjusting a training plan based on HRV can lead to better performance than just sticking to a pre-planned training program. So how can you get started with measuring your own HRV?
There are several technological options to measure HRV. I used a smartphone app called HRV4training, which not only accurately measures morning HRV (via your camera) but also helps you relate the outcome to a cause (training, stress, alcohol, poor sleep etc.). If you don’t want to adjust your morning routine, a non-stop wearable fitness tracker could help. You maybe already have a compatible fitness tracker like some Garmin Vívoactive, Fenix or Forerunners or Apple watch. Just google your device + HRV and you will soon find the possibilities. If you consider buying an HRV compatible fitness tracker, definitely check out the Whoop Strap 3.0.
Would you like to read more about recovery? Check all recovery content!
Founder of Molab, Human Movement Scientist and a sports enthusiast.